Remarkable Breakdown Voltage on AlN/AlGaN/AlN double heterostructure

Ultra wide band gap (UWBG) materials such as AlN are part of a class of materials that have a larger band gap than conventional wide band gap (WBG) materials such as GaN, allowing higher operating voltages. In this work we present the fabrication and DC / high voltage characterizations of AlN/AlGaN/AlN double heterostructure that are regrown by metalorganic chemical vapor deposition on AlN/sapphire. A buffer breakdown about 1100V with low leakage current for a spacing below 2µm is reported, which corresponds to a breakdown field about 6 MV/cm. Furthermore, transistors have been successfully fabricated on this heterostructure with low leakage current and low on-resistance. A breakdown voltage of 4.5kV with an off-state leakage current below 0.1 µA/mm have been indeed achieved. These results that AlGaN-channel HEMTs are promising for high power, high temperature future applications.